1. Field of the Invention
The invention relates to novel aminated polyamines having valuable therapeutic and other biological properties.
2. Discussion of the Prior Art
In recent years, a great deal of attention has been focused on the polyamines, e.g., spermidine, norspermidine, homospermidine, 1,4-diaminobutane (putrescine) and spermine. These studies have been largely directed at the biological properties of the polyamines probably because of the role they play in proliferative processes. It was shown early on that the polyamine levels in dividing cells, e.g., cancer cells, are much higher than in resting cells. See Janne et al, A. Biochim. Biophys. Acta., Vol. 473, page 241 (1978); Fillingame et al, Proc. Natl. Acad. Sci. U.S.A., Vol. 72, page 4042 (1975); Metcalf et al, J. Am. Chem. Soc., Vol. 100, page 2551 (1978); Flink et al, Nature (London), Vol. 253, page 62 (1975); and Pegg et al, Polyamine Metabolism and Function, Am. J. Cell. Physiol., Vol. 243, pages 212-221 (1982).
Several lines of evidence indicate that polyamines, particularly spermidine, are required for cell proliferation: (i) they are found in greater amounts in growing than in non-growing tissues; (ii) prokaryotic and eukaryotic mutants deficient in polyamine biosynthesis are auxotrophic for polyamines; and (iii) inhibitors specific for polyamine biosynthesis also inhibit cell growth. Despite this evidence, the precise biological role of polyamines in cell proliferation is uncertain. It has been suggested that polyamines, by virtue of their charged nature under physiological conditions and their conformational flexibility, might serve to stabilize macromolecules such as nucleic acids by anion neutralization. See Dkystra et al, Science, Vol. 149, page 48 (1965); Russell et al, Polyamines as Biochemical Markers of Normal and Malignant Growth (Raven, N.Y., 1978); Hirschfield et al, J. Bacteriol., Vol. 101, page 725 (1970); Hafner et al, J. Biol. Chem., Vol. 254, page 12419 (1979); Cohn et al, J. Bacteriol., Vol. 134, page 208 (1978); Pohjatipelto et al, Nature (London), Vol. 293, page 475 (1981); Mamont et al, Biochem. Biophys. Res. Commun., Vol. 81, page 58 (1978); Bloomfield et al, Polyamines in Biology and Medicine (D. R. Morris and L. J. Morton, eds., Dekker, New York, 1981), pages 183-205; Gosule et al, Nature, Vol. 259, page 333 (1976); Gabbay et al, Ann. N.Y. Acad. Sci., Vol. 171, page 810 (1970); Suwalsky et al, J. Mol. Biol., Vol. 42, page 363 (1969); and Liquori et al, J. Mol. Biol., Vol. 24, page 113 (1968).
However, regardless of the reason for increased polyamine levels, the phenomenon can be and has been exploited in chemotherapy. See Sjoerdsma et al, Buttenvorths Int. Med. Rev.: Clin. Pharmacol. Thera., Vol. 35, page 287 (1984); Israel et al, J. Med. Chem., Vol. 16, page 1 (1973); Morris et al, Polyamines in Biology and Medicine, Dekker, New York, page 223 (1981); and Wang et al, Biochem. Biophys. Res. Commun., Vol. 94, page 85 (1980).
Because of the role the natural polyamines play in proliferation, a great deal of effort has been invested in the development of polyamine analogues as anti-proliferatives>Cancer Res., Vol. 49, “The role of methylene backbone in the anti-proliferative activity of polyamine analogues on L1210 cells,” Bergeron et al, pages 2959-2964 (1989); J. Med. Chem., Vol. 31, “Synthetic polyamine analogues as antineoplastics,” Bergeron et al, pages 1183-1190 (1988); Polyamines in Biochemical and Clinical Research, “Regulation of polyamine biosynthetic activity by spermidine and spermine—a novel antiproliferative strategy,” Porter et al, pages 677-690 (1988); Cancer Res., Vol. 49, “Major increases in spermidine/spermine-N.sup.1-acetyl transferase activity by spermine analogues and their relationship to polyamine depletion and growth inhibition in L1210 cells,” Basu et al, pages 6226-6231 (1989); Biochem. J., Vol. 267, “Induction of spermidine/spermine N.sup.1-acetyl transferase activity in Chinese-hamster ovary cells by N.sup. 1,N.sup.11-bis(ethyl)norspermine and related compounds,” Pegg et al, pages 331-338 (1990); Biochem. J., Vol. 268, “Combined regulation of ornithine and S-adenosylmethionine decarboxylases by spermine and the spermine analogue N.sup.1 N.sup.12-bis(ethyl)spermine,” Porter et al, pages 207-212 (1990); Cancer Res., Vol. 50, “Effect of N.sup.1,N.sup.14-bis(ethyl)-homospermine on the growth of U-87 MG and SF-126 on human brain tumor cells,” Basu et al, pages 3137-3140 (1990); and Biochem. Biophys. Res. Commun., Vol. 152, “The effect of structural changes in a polyamine backbone on its DNA binding properties,” Stewart, pages 1441-1446 (1988)!. These efforts have included the design of new synthetic methods>J. Org. Chem., Vol. 45, “Synthesis of N.sup.4-acylated N.sup.1,N.sup.8-bis(acyl)spermidines: An approach to the synthesis of siderophores,” Bergeron et al, pages 1589-1592 (1980); Synthesis, “Reagents for the selective acylation of spermidine, homospermidine and bis->3-aminopropyl!amine,” Bergeron et al, pages 732-733 (1981); Synthesis, “Reagents for the selective secondary functionalization of linear triamines,” Bergeron et al, pages 689-692 (1982); Synthesis, “Amines and polyamines from nitriles,” Bergeron et al, pages 782-785 (1984); J. Org. Chem., Vol. 49, “Reagents for the stepwise functionalization of spermidine, homospermidine and bis->3-aminopropyl!amine,” Bergeron et al, page 2997 (1984); Accts. Chem. Res., Vol. 19, “Methods for the selective modification of spermidine and its homologues,” Bergeron, pages 105-113 (1986); Bioorg. Chem., Vol. 14, “Hexahydropyrimidines as masked spermidine vectors in drug delivery,” Bergeron et al, pages 345-355 (1986); J. Org. Chem., Vol. 53, “Reagents for the stepwise functionalization of spermine,” Bergeron et al, pages 3108-3111 (1988); J. Org. Chem., Vol. 52, “Total synthesis of (.+−.)-15-Deoxyspergualin,” Bergeron et al, pages 1700-1703 (1987); J. Org. Chem., Vol. 56, “The total synthesis of Alcaligin,” Bergeron et al, pages 586-593 (1991); and CRC Handbook on Microbial Iron Chelates, “Synthesis of catecholamide and hydroxamate siderophores,” Bergeron et al, pages 271-307 (1991)! for the production of these analogues, as well as extensive biochemical studies focused on the mechanism by which these compounds act>Cancer Res., Vol. 46, “A comparison and characterization of growth inhibition by .alpha.-Difluoromethylomithine (DFMO), and inhibitor of ornithine decarboxylase and N.sup.1,N.sup.8-bis(ethyl)spermidine (BES), an apparent regulator of the enzyme,” Porter et al, pages 6279-6285 (1986); Cancer Res., Vol. 47, “Relative abilities of bis(ethyl) derivatives of putrescine, spermidine and spermine to regulate polyamine biosynthesis and inhibit L1210 leukemia cell growth,” Porter et al, pages 2821-2825 (1987); Cancer Res., Vol. 49, “Correlation between the effects of polyamine analogues on DNA conformation and cell growth,” Basu et al, pages 5591-5597 (1989); Cancer Res., Vol. 49, “Differential response to treatment with the bis(ethyl)polyamine analogues between human small cell lung carcinoma and undifferentiated large cell lung carcinoma in culture,” Casero et al, pages 639-643 (1988); Mol. Pharm., Vol. 39, “Selective cellular depletion of mitochondrial DNA by the polyamine analog, N.sup.1,N.sup.12-bis(ethyl)spermine, and its relationship to polyamine structure and function,” Vertino et al, pages 487-494 (1991); Biochem. and Biophys. Res. Comm., Vol. 157, “Modulation of polyamine biosynthesis and transport by oncogene transfection,” Chang et al, pages 264-270 (1988); and Biopolymers, Vol. 26, “Structural determinants of spermidine-DNA interactions,” Vertino et al, pages 691-703 (1987)!. The mechanistic investigations have encompassed uptake studies, impact on polyamine analogues on polyamine pools and polyamine biosynthetic enzymes, as well as their effects on translational and transcriptional events.
Anti-neoplastic analogues of the naturally occurring polyamines, pharmaceutical compositions and methods of treatment are also disclosed in the following pending patent application Ser. No. 08/231,692 filed Apr. 25, 1994, as well as in U.S. Pat. No. 5,091,576 issued Feb. 25, 1992; U.S. Pat. No. 5,128,353 issued Jul. 7, 1992; U.S. Pat. No. 5,173,505 issued Dec. 22, 1992 and U.S. Pat. No. 5,962,533, issued Oct. 5, 1999. The disclosures of each of the foregoing applications and patents are incorporated herein by reference.
Many of the biologically and pharmacologically valuable polyamines, however, present troublesome metabolic properties in that they are metabolized after administration to the whole animal to potentially toxic metabolites, several of which have a protracted half-life in animals.
Diethylnorspermine (DENSPM) and its metabolites are found in all of the tissues of mice treated with the drug, with the liver and kidney having the highest level of metabolites. These catabolic products included N.sup.1-ethylnorspermine (MENSPM), N.sup.1-ethylnorspermidine (MENSPD), N.sup.1-ethyl-1,3-diaminopropane (MEDAP) and norspermidine (NSPD), suggesting that DENSPM is metabolized (FIG. 1) by (1) N-deethylation and (2) stepwise removal of 3-aminopropyl equivalents by spermine/spermidine N.sup.1-acetyl transferase (SSAT)/polyamine oxidase (PAO).
Diethylhomospermine is an example of a polyamine recently found to have potent activity as an anti-neoplastic and anti-diarrheal agent. Its metabolic profile indicates the highest concentration of the polyamine and its principal metabolites, N.sup.1-ethylhomospermine (MEHSPM) and homospermine (HSPM), in the liver and kidney. N-deethylation is a key metabolic step in processing DEHSPM (see FIG. 2); however, HSPM does not undergo further metabolism. The accumulation and persistence of HSPM in the tissues of DEHSPM-treated animals is especially striking. Even three weeks after a seven day schedule of DEHSPM, 35% of the drug administered to mice remains in the liver and kidney as drug or metabolites. Interestingly, 90% of the drug remaining in the animal at this time is in the form of HSPM. It is quite clear that the increased chronic toxicity of DEHSPM over N.sup.1,N.sup.4-diethylnorspermine (DENSPM) is related to the buildup of HSPM.
The key to a less toxic DEHSPM-like therapeutic agent is one in which the metabolites can be quickly cleared from the tissues. Again, because of the aminobutyl fragments of HSPM, this metabolite cannot be processed through the polyamine biosynthetic network; thus, it remains in the tissues for protracted periods of time. Neither the primary nor the secondary nitrogens of HSPM offer an opportunity for facile conversion to an easily cleared metabolite. Certainly, the methylene backbones cannot be easily oxidized to an excretable metabolite.
It is an object of the present invention to provide novel derivatives of therapeutically and biologically active polyamines which are metabolized to products quickly and easily cleared from animal tissues.
It is another object of the invention to provide novel pharmaceutical compositions and methods of treating human and non-human animals with the novel polyamine derivatives.